docs: def get_mean_and_stddevs(self, sites, rup, dists, imt, stds_types):
          """
          See :meth:`superclass method
          <.base.GroundShakingIntensityModel.get_mean_and_stddevs>`
          for spec of input and result values.
          """
          # Prepare sites
          sites_rock = copy.deepcopy(sites)
          sites_rock.vs30 = np.ones_like(sites_rock.vs30) * 760.
          # compute mean and standard deviation
          mean, stddvs = self.gmpe.get_mean_and_stddevs(sites_rock, rup, dists,
                                                        imt, stds_types)
          if not str(imt) == 'PGA':
              # compute mean and standard deviation on rock
              mean_rock, stddvs_rock = self.gmpe.get_mean_and_stddevs(
                  sites_rock, rup, dists, imt, stds_types)
          else:
              mean_rock = mean
          fa = self.BA08_AB06(sites.vs30, imt, np.exp(mean_rock))
          mean = np.log(np.exp(mean) * fa)
          return mean, stddvs